The U.S. Supreme Court on Tuesday took up the latest in a series of voting rights cases, agreeing to hear Ohio's bid to revive the Republican-led state's policy of purging people from voter registration lists if they do not regularly cast ballots.

Civil liberties advocates who challenged Ohio's policy said it illegally erased voters from registration rolls and unlawfully disenfranchised minorities and poor people who tend to back Democratic candidates.

The justices will review a U.S. appeals court ruling that Ohio's policy ran afoul of a 1993 law called the National Voter Registration Act, which Congress passed to make it easier for Americans to register to vote.

A Reuters analysis last year found that in Ohio's three largest counties, which include Cleveland, Cincinnati and Columbus, voters were struck from the rolls in Democratic-leaning neighborhoods at roughly twice the rate as in Republican neighborhoods under the policy.

Ohio officials argued that canceling registrations for voters deemed inactive for six years helped clear from voting rolls those who had moved away or died.

In September 2016, ahead of the U.S. presidential election, the 6th U.S. Circuit Court of Appeals in Cincinnati ruled that Ohio's policy was unlawful.

Democrats have accused Republicans of taking steps at the state level, including laws imposing new requirements on voters such as presenting certain types of government-issued identification, intended to suppress the vote of minorities, the poor and others who generally favor Democratic candidates.

The Supreme Court will be critical in determining whether such policies are lawful, already acting in some cases and considering taking up more.

ACLU lawsuit

The American Civil Liberties Union last year sued Ohio Secretary of State Jon Husted, arguing that the state was violating the 1993 law, which prohibits states from striking registered voters "by reason of the person's failure to vote." The 6th Circuit agreed.

Husted called the Supreme Court's decision to hear his state's appeal encouraging. "Maintaining the integrity of the voter rolls is essential to conducting an election with efficiency and integrity," Husted said in a statement.

Under Ohio's policy, if registered voters miss voting for two years, they are sent registration confirmation notices. If they do not respond and do not vote over the following four years, they are removed from the rolls.

Husted has said Ohio's policy has been in place since the 1990s under both Republican and Democratic secretaries of state.

Freda Levenson, legal director of the ACLU of Ohio, expressed confidence that the Supreme Court would uphold the 6th Circuit ruling. "Ohio's purge of eligible voters has served as a powerful mechanism of voter suppression," Levenson said in a statement.

Husted said he has made maintaining accurate voter rolls a priority in order to increase election integrity and voter confidence, including removing nearly 560,000 dead people from the rolls and resolving instances of more than 1.65 million voters who were registered more than once.

The suit said the policy led to the removal of tens of thousands of people from the voter rolls in 2015, including one of the lead plaintiffs, Larry Harmon, a software engineer and U.S. Navy veteran who was blocked from voting in a state marijuana initiative in 2015.

FILE - People cast ballots as early absentee voting began ahead of the U.S. presidential election in Medina, Ohio, Oct. 12, 2016.

Republican Donald Trump won Ohio in last November's presidential election.

'Motor voter' law

The National Voter Registration Act, dubbed the "motor voter" law when it was enacted, required states to permit registration by mail or when eligible people apply for or renew a driver's license, or visiting certain government agencies or military recruiting offices.

In another voting rights case, the justices on May 22 ruled that Republicans in North Carolina unlawfully took race into consideration when drawing congressional district boundaries, concentrating black voters in an improper bid to diminish their statewide political clout.

The justices on May 15 rebuffed a Republican bid to revive North Carolina's strict voter identification law that a lower court found deliberately discriminated against black voters.

The justices on March 1 ordered a lower court to reassess whether Virginia's Republican-led legislature unlawfully tried to dilute the power of black voters. The justices threw out the lower court's decision upholding 12 state legislature districts.

The justices will hear arguments in the Ohio case in their next term, which starts in October.